CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
Same classic 45-degree pattern, dark version.
Source Luke McDonald
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Kaleidoscope Prismatic Abstract No Background
Source GDJ
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
Sharp pixel pattern, just like the good old days.
Source Paridhi
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed